The method and apparatus described herein relate to the configuration and operation of a sensor head component employable in a monitoring tool assembly, and more particularly to sensor head component configured as an accessory configured to perform functions on other sensor head components.
An ever increasing emphasis is being placed on systematic monitoring of environmental conditions in relation to ground and surface water resources. Examples of some situations where monitoring of conditions of a water resource may be desired include environmental monitoring of aquifers at an industrial site to detect possible contamination of the aquifer, monitoring the flow of storm water runoff and storm runoff drainage patterns to determine the affects on surface water resources, monitoring the flow or other conditions of water in a watershed from which a municipal water supply is obtained, monitoring lake, stream or reservoir levels, and monitoring ocean tidal movements.
These applications often involve taking data over an extended time and often over large geographic areas. For many applications, data is collected inside of wells or other holes in the ground. A common technique is to drill, or otherwise excavate, a number of monitoring wells and insert down-hole monitoring tools into the wells to monitor some condition of the water in the wells. One desirable feature of such a tool assembly is the capability to monitor one or more conditions at the site where the tool assembly has been located. In addition to such parameters as water level, temperature, and turbidity, it is also desirable to measure other parameters such water quality (i.e., the amount of contaminants in the water) which can be measured through the use of a conductivity sensor or other ion selective electrodes (ISE) sensors specially configured to detect the presence of one or more specific contaminants.
A significant issue with regards to the employment of tool assemblies for monitoring water quality conditions is the relatively high cost of each unit. One reason for the high cost is that they use expensive components and designs that frequently require a significant amount of expensive machining and assembly. The tools assemblies often require the complex assembly of many components and significant manufacturing expenses are often required to provide structures for coupling the components and for electrically interconnecting the components. Furthermore, assembly and disassembly of components of the down-hole tools frequently require the use of wrenches or other tools, and sometimes special tools. This complicates use of the down-hole monitoring tools, and providing features on the down-hole tools to accommodate tools required for assembly and disassembly often requires machining, which significantly adds to manufacturing costs. Furthermore, electrical interconnections between components typically require special keying of the components, or of the electrical connectors between the components which result in difficulty of use and a possibility for tool damage or malfunction due to misalignment.
In addition to the high cost of monitoring wells and down-hold monitoring tools, a significant amount of ongoing labor is typically required to maintain the tools and to obtain and use data collected by the tools. For example, it is frequently necessary to have someone visit the monitoring wells at periodic intervals to make sure that the tools are still working and to obtain data collected by the tools. Data must then be analyzed for use. The frequency between visits to a well may be a function of a number of variables, such as the reliability of the tools, the frequency with which batteries need to be replaced, and the capacity of the tools to collect and either store or provide access to the data. Moreover, many down-hole tools are difficult to service and must be returned to manufacturers and distributors for even relatively simple service tasks such as changing batteries in the tool. There is a significant need for tools that are simple to manufacture and assemble, require less attention, and are easier to service.
Described herein is an apparatus and method for performing functions on one or more sensor head components interconnected in a sensor head for a monitoring tool assembly. The apparatus may comprise an interchangeable sensor head component specially configured as an accessory which includes an electrical connector portion for interconnecting with the sensor head. Extending from the electrical connector portion is a body portion configured to enclose a motor. The motor is further in connection with an accessory arm of a predetermined length and positionable at particular height so as to be movable by the motor in a target area.
In one configuration of the invention, the accessory is specially configured for cleaning and/or removing debris from other sensor head components interconnected in the sensor head of the monitoring tool assembly. As such, the accessory arm may be configured to hold a cleaning element, such as a cloth, brush, and/or abrasive material, at an end opposite the point where the accessory arm connects with the motor. Upon manual or automatic activation of the motor, the cleaning element may cyclically move within the target area in a manner whereby a particular surface of the interchangeable sensor head component is cleaned.
For example, one or more interchangeable sensor head components interconnected in a sensor head may include windows or other surfaces which accumulate debris, such as algae or other waterborne particles, during the operation of the monitoring tool assembly. More specifically, sensors such as turbidity and pH may employ windows during their operation while sensors such as dissolved oxygen may use of membranes. The surfaces to be cleaned may be positioned in a target area for the accessory arm, such that upon activation of the motor the cleaning element contacts the particular surface and moves in a manner to remove the debris.
The cleaning element may be further configured to include one or more layers of elastic material. The elastic material provides that upon compression of the cleaning element between the accessory arm and the surface to be cleaned, an expansive force is exerted by the flexible materials so as to increase the force exerted upon the surface by the cleaning element for removing debris.
In another configuration of the invention, the motor is configured to rotate the accessory arm in a radius about the body portion. In this configuration, one or more sensor head components interconnected in the sensor head are positioned within the radius of the accessory arm and may be contacted by the cleaning element. In particular, the accessory described herein may be positioned in a central port in the sensor head for the monitoring tool assembly. One or more of the sensor head components may be interconnected in sensor ports around the central port, whereby a maximum number of sensor head components are contactable by the cleaning element during its operation.
In yet another configuration of the invention, the accessory arm may be configured to move a calibration a device such as a surface which reflects light at a known wavelength. With sensors that may be periodically calibrated, such as a turbidity sensor, the motor may be activated to move the calibration surface into a target area such as over a window behind which the sensor being calibrated is located. Once the calibration process is complete, the motor may then again be activated and the calibration surface moved out of the target area.
In the configuration of the invention where the motor is configured to rotate the accessory arm, the motor may be further configured to include one or more positional sensors which generate signals indicative of the rotational position of the drive shaft in the motor. This information is especially useful during the calibration process whereby that calibration surface may be positioned in a particular target area. Alternatively, positional information for the actuator arm may also be generated based on signals from one or more sensors incorporated in sensor head components interconnected in the sensor head.
For example, the magnitude of the signals generated by a turbidity sensor is directly related to the amount of light detected through the window. As the accessory arm moves in front of the window of the turbidity sensor, this significantly affects the amount of light detected. The monitoring tool assembly may process this information in conjunction with other known information such as the radius of the accessory arm, the RPMs of the accessory arm, and the direction of movement of the arm, in order to generate positional information for the actuator arm. This information may then be further employed for positioning the accessory arm in a selected position.
The body portion may be further configured to include one or more electronic components such as a memory device upon which identification and other information relating to the sensor head component may be stored and accessed. With regards to the accessory component described herein, this information may include such things as model number and performance information for the particular accessory.